NAFLD seen in some patients without metabolic syndrome

Morbidly obese patients without metabolic syndrome who decided to undergo gastric bypass surgery had high rates of fatty liver disease, according to a new study.

Researchers looked at 445 patients who were morbidly obese (mean body mass index 48 kg/m2) who had been selected for Roux-en-Y gastric bypass surgery, and who had non-alcoholic fatty liver disease (NAFLD). Nearly three-quarters (73%) of them had NAFLD, as tested by a liver biopsy, reported Kamran Qureshi, MD, of Temple University School of Medicine in Philadelphia, and Gary Abrams, MD, of the Greenville Health System Gastroenterology & Liver Center in Greenville, S.C.

Among those patients, 56% had fatty liver alone and 17% had non-alcoholic steatohepatitis (NASH), they explained in a poster presentation at the American College of Gastroenterology meeting.

In addition, 24% of these morbidly obese patients who underwent surgery did not have metabolic syndrome, they said.

A separate study at the meeting found that BMI may serve as a predictor of mortality for patients with NAFLD, but only for those who were extremely obese.

No Metabolic Syndrome

In the study by Qureshi and Abrams, all patients (mean age 38) consented to undergoing intraoperative liver biopsy. The authors identified 105 patients who did not have metabolic syndrome as defined by the International Diabetes Foundation. Obesity (mean BMI 48 kg/m2) was the only component of metabolic syndrome present in all patients. Five patients had fibrosis.

They noted that not all obese patients have insulin resistance or will develop metabolic syndrome, and that NAFLD is considered a hepatic manifestation of metabolic syndrome. They aimed to evaluate how prevalent NAFLD is in those who are obese without metabolic syndrome

In the study, 22% of those with NAFLD didn't have any other metabolic components associated with metabolic syndrome, while 36% had low HDL, 27% had hypertension, 8% had high triglycerides, and 6% had dysglycemia. None of the patients were on dyslipidemia medication, and three were taking diabetes medications.

"Though there is selection bias in this study population, yet the large size and availability of complete clinical and histologic parameters make our findings significant," the authors wrote. "Diagnosis of dysglycemia in such [patients] suggests presence of insulin resistance, and may have NASH."

NAFLD: BMI and Mortality Risk

In the second study, Ashley Davis-Yadley, MD, at the University of South Florida Morsani College of Medicine in Tampa, and colleagues used 1988-1994 data from the third National Health and Nutrition Examination Survey (NHANES). In their analysis, they included 818 adults, ages 20-74, "with presumed NAFLD on ultrasonography after all other causes of liver disease were excluded."

The findings were adjusted for age, sex, ethnicity, smoking status, alcohol consumption, cholesterol, and blood pressure. There were 818 cases and 187 deaths at the end of follow-up.

Those who were most obese (BMI >40 kg/m2) and had severe NAFLD were at an increased risk of mortality (risk ratio 3.33, 95% CI 1.56-7.11, P=0.0026) compared with normal-weight people. There was no significant increase in mortality for those with NAFLD who were overweight (25-29.9 kg/m2, RR 2.06, 95% CI 0.89-4.75) or in obesity class I (30-34.9 kg/m2, 1.45, 95% CI 0.60-3.49), according to the researchers.

"The finding goes along with the consensus that the metabolic syndrome, diabetes, and obesity all contribute to fatty liver disease and eventually to increased mortality," Davis-Yadley told MedPage Today.

Last year, a separate study found that those who were underweight and who had NAFLD were twice as likely to die than those with the disease who were overweight or obese.

Those results surprised researchers, who had assumed that those with NAFLD who weren't overweight or obese would have better outcomes than those who were. In addition, prevalence of NAFLD has increased along with obesity. But researchers noted that most patients with NAFLD aren't overweight and that the natural history of obese patients with NAFLD hasn't been studied extensively.

"The next step is to analyze why this association is present, and to look at the molecular mechanisms behind it," Davis-Yadley said. Also, to look "at different proteins to understand why metabolic syndrome and an increased BMI go along with increased mortality in NAFLD patients," she added.

Qureshi and Abrams disclosed no relevant relationships with industry.

Davis-Yadley and co-authors disclosed no relevant relationships with industry.

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